Thank you Kypfer - I needed that encouragement 
Well, I now got a note or three hooray!
My wife heard me complain over the last few days, and just an hour or so ago asked me to hand her one of the pipes. In about five seconds, out came a robust note!
She had played some fife as a child - didn’t stick with it. Anyway, she showed me and had me blowing a note in short order I’m in love all over again 
So my joy at being able to actually raise the occasional note (as opposed to merely wind) became somewhat muted, as I continue to struggle with figuring out embouchure …
So far, I can most reliably raise notes by completely collapsing my lower lip, developing a gigantic overbite, and puffing out my cheeks like Dizzy Gillespie. I have decided not to go that direction, however, as I suspect it may not be the best idea 
So still trying to develop the more conventional way. I may have had a bit of a breakthrough last night, but unfortunately as it was very late I shall have to wait to explore it further
Oh, BTW … back before I was able to get any note, I got fed up and cut an “access panel” off the bottom of the pipe. I then took scissors and reamed the blow hole upwards, from inside. So it’s undercut now, @#$% it!
Taped the panel (really a sort of elliptical section) carefully back in place, and it’s that modified pipe that my wife easily got notes out of, so I don’t think I destroyed it too badly.
(For those keeping score, that means I now have a. two PVC pipes with blow holes - one violently undercut, one not - and b. the Yamaha “fife”.)
Well, that’s determination re: the undercut! Really a make-work way to attack it, though - I mean, sandpaper wrapped round a pencil and approaching from above would have been a load easier! Also, FWIW, undercutting will not per se help you to learn to generate a tone. A tidy, straight-cut hole is no easier or harder to do that on.
I know I’ve told this story here and elsewhere umpteen times (had hoped you’d use the Search tool for old threads on embouchure help - in which case you’d probably have seen it…): when I first started on transverse flute, I was given a rather battered school/County Music Service Bohm flute (a Boosey & Hawkes starter level jobbie, IIRA - Yamahas were only just starting to appear with a good reputation and the more advanced [Grade V +] students mostly still aspired to a Gemeinhardt as a next level toot!) for the summer holidays (after my A levels, age 17+, 1976! [drought summer!]) and a copy of Tune a Day Book 1 for flute. I spent about 2 weeks mostly holed up in my bedroom hyperventilating and getting headaches, using just the head-joint as the book prescribed and working on learning to make a sound.
One gets there in the end, but far quicker with an experienced eye to advise you as your face muscles learn new shapes and control. A major point to remember is DO NOT “BLOW”, and certainly not hard. Just breathe out through as narrow and focussed an aperture as you can persuade your lips to form, and use a mirror to look at what you’re doing in close-up. Whether it comes naturally/easily to you or not, it is just like any other muscle training - “muscle memory”, fine control and fitness all take training in the callisthenic sense. Little and often is the best way - so if you can carry the factory made “fife” or a self-made head-joint substitute section of pipe with stopper and hole around with you and whip it out and practice for a few minutes whenever you get a chance through the day, do!
I employed a similar technique (four years earlier & I was four years older).
2 weeks, eh? I don’t remember how long it took me.
I know that after five months I could play along for a couple or so songs before I needed to rest.
Notes! Actual notes are emerging this evening - hooray
(Granted, emerging mostly from the Yamaha, but some from my homemade as well!)
well it’s all downhill then
Something resembling actual tunes starting to emerge as well … though standing in front of the mirror, finally striking notes and afraid to move for fear of losing it, I can only ever seem to remember “Brian Boru’s March”.
soon you’ll be complaining 'cause ‘ya can only play for 5 minutes’ before it goes out on ya!
That’s when I’ll put it down for a bit and pick up the whistle 